/Engine/Source/Developer/TargetPlatform/Public/Interfaces/IShaderFormat.h
Executes all shader preprocessing steps; only called if SupportsIndependentPreprocessing returns true
virtual bool PreprocessShader ( const [FShaderCompilerInput](API\Runtime\RenderCore\FShaderCompilerInput) & Input, const [FShaderCompilerEnvironment](API\Runtime\RenderCore\FShaderCompilerEnvironment) & Environment, [FShaderPreprocessOutput](API\Runtime\RenderCore\FShaderPreprocessOutput) & PreprocessOutput ) const